On Fri, Sep 22, 2023 at 12:15:34PM -0300, Jason Gunthorpe wrote: > On Fri, Sep 22, 2023 at 11:13:18AM -0400, Michael S. Tsirkin wrote: > > On Fri, Sep 22, 2023 at 12:25:06PM +0000, Parav Pandit wrote: > > > > > > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > > Sent: Friday, September 22, 2023 5:53 PM > > > > > > > > > > > And what's more, using MMIO BAR0 then it can work for legacy. > > > > > > > > Oh? How? Our team didn't think so. > > > > > > It does not. It was already discussed. > > > The device reset in legacy is not synchronous. > > > The drivers do not wait for reset to complete; it was written for the sw backend. > > > Hence MMIO BAR0 is not the best option in real implementations. > > > > Or maybe they made it synchronous in hardware, that's all. > > After all same is true for the IO BAR0 e.g. for the PF: IO writes > > are posted anyway. > > IO writes are not posted in PCI. Aha, I was confused. Thanks for the correction. I guess you just buffer subsequent transactions while reset is going on and reset quickly enough for it to be seemless then? -- MST
